This invention relates generally to a system for dispensing fluids, and more particularly to a sealant delivery system and apparatus for application of a sealant compound material to container lids and closures of the type disclosed in U.S. Pat. Nos. 4,262,629 and 4,840,138, the disclosures of which are incorporated herein by reference.
In general, the apparatus of U.S. Pat. Nos. 4,262,629 and 4,840,138 comprises a rotary can lid feed mechanism having a series of pockets which are advanced through a downstacker area to laterally shift each lowermost lid in succession of the stack of lids along an arcuate guide path into each of a series of shallow recesses formed in a rotary chuck table. The rotary chuck table has a series of lift chucks disposed in normally lowered position beneath the recesses, and a rotary drive is operative to synchronously rotate the table and lift chucks at a predetermined rate of speed. A cam member located in the path of travel of the lift chucks is operative to advance each lift chuck in succession when it is received at a first station between a normally lowered position and a raised position through a distance corresponding to two stations, after which the lid is lowered as it is advanced to a third station and discharged into a collection area. The empty recess then continues through a distance corresponding to three more stations before it picks up another can lid. An upper sealant gun assembly includes a spring-loaded chuck aligned with each recess so as to be engageable with each lid as it is raised by the lift chuck to activate an associated sealant gun in response to such engagement. The sealant is discharged from the gun as the can lid is caused to rotate about its own axis by rotation of the lift chuck through the first two stations so as to uniformly deposit the lining material into the groove of each can lid in succession. Again, following application of the sealant, the can lid is lowered by the lift chuck, then disengaged so as to permit the can lid to be discharged from the table preferably by the rotary speed of rotation of the table into a discharge or collection area. Feed interrupt mechanism is provided for interrupting advancement of the can lids from the downstacker area in passing in the event of misalignment of a lid; also, an interrupt mechanism is provided in association with the sealant gun to interrupt delivery of sealant in the event that the can lid is not properly aligned with respect to a recess on the chuck table. Preferably, both interrupt mechanisms are controlled by a common sensor in the rotary feed mechanism; however, a separate sensor is provided on the upper chuck assembly to interrupt supply of sealant. Apparatus of this type has been successfully employed with sealant material made from a non-abrasive, non-corrosive solvent base compound which does not present any significant problems in the sealant delivery system.
The apparatus of U.S. Pat. No. 4,840,138 provides a sealant dispensing system for use with a conventional rotary-type sealant-applying machine wherein a plurality of circumferentially spaced sealant supply hose means connect a sealant supply means to a plurality of circumferentially spaced sealant dispensing head means which rotate about a central axis of rotation. The sealant supply means is located in coaxial relationship with the central axis of rotation and rotates thereabout and comprises an elongated vertical rotatable supply chamber means in which a supply of sealant is maintained under pressure by a supply of compressed air for delivery to the sealant dispensing head means through the supply hose means.
A spindle means is attached to the supply chamber means for rotation therewith and extends into a non-rotatable support housing with bearing means mounted therebetween. The support housing means and the spindle means have coaxial aligned central passages which are coaxial with the central axis of rotation. Sealing means are mounted between the spindle means and the support housing means to prevent escape of air from the air passage means. Sealant is delivered to the supply chamber means through a non-rotatable central tubular passage means mounted in the housing and spindle passage means in coaxial alignment with the central axis of rotation. Air is delivered to the supply chamber means through an annular passage means circumjacent the tubular passage means. Electrical sensing means are provided to monitor the amount of sealant in the supply chamber means and to cause additional amounts of sealant to be automatically delivered to the supply chamber when a lower chamber level of sealant is detected and to terminate delivery when an upper maximum sealant level is reached. The sensing means are activated by contact with the conductive water-base sealant compound. The construction and arrangement is such that the sealant does not contact any part of the spindle means nor the support housing means nor the bearing and sealing means associated therewith.
The nozzle apparatus of U.S. Pat. Nos. 4,262,629 and 4,840,138 was actuated between open and closed positions by a mechanical linkage and the size of the dispensing opening was adjusted by a mechanical linkage. Some attempts have been made to provide electric operated pneumatic and/or hydraulic actuation systems.